1. Technical Field
The present invention relates to a power supply identification apparatus in an electric device having two kinds of power input terminals, for controlling an initial ON/OFF state corresponding to the type of power supplies.
2. Related Art
Some data storage devices such as hard disc devices can be built in personal computers and are attached externally to personal computers to be operated. In general, powers of such data storage devices built in the personal computers are supplied from personal computer main bodies, and powers of the external data storage devices are supplied from AC power supplies.
Such data storage devices are activated by powers supplied from personal computer main bodies or AC power supplies. That is to say, when the data storage devices are built in the personal computers, power switches of the personal computer main bodies activate the data storage devices. In this case, however, both power switches of the personal computer main bodies and power switches of the data storage devices should be turned on. On the other hand, when the data storage devices are externally attached to the personal computers, the data storage devices are activated by supply from the AC power supplies. Needless to say, also in this case, power switches of the data storage devices should be turned on.
Japanese Patent Application Laid-Open No. 05-241696 discloses a technique that detects connection/disconnection of the AC power immediately when an AC adapter (AC power) is pulled out and further is connected after a personal computer is activated. However, the personal computer disclosed in Japanese Patent Application Laid-Open No. 5-241696 does not control ON/OFF states of peripheral devices such as the data storage device according to types of power supplies to be connected, for example, types of AC power supplies and another power supplies.
Conventionally, an electric device having two kinds of different power input terminals such as a data storage device can detect connection/disconnection of a power supply to the respective power input terminals and select any one of power supplies to be used. However, the electric device cannot be activated nor prevent activation according to a type of the power input terminal to which the power is currently supplied.
It is an object of the present invention to provide a power supply identification apparatus that can automatically identify a power of two kinds of powers that is input, and can control an ON/OFF state of activation in an entire electric device according to the type of the input power.